<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>数据类型-特殊值</title>
    <script type="text/javascript">
        //三种特殊值类型
        var name;
        console.log("name="+name)//undefined类型
        var address=null
        console.log("address="+address)//null类型
        console.log(10*"sds") //NaN类型，即不是not a number
    </script>
</head>
<body>

</body>
</html>